Sensation and Perception

Vocabulary practice flashcards covering sensation, sensory thresholds, hearing and vision mechanisms, pain and chemical senses, perceptual organization, and depth cues.

Sensation

The process by which sensory receptors and the nervous system receive and represent stimulus energy from the environment.

Bottom-Up Processing

Information processing that begins at sensory receptors and works up to brain integration; it is data-driven and progresses from individual parts to the whole.

Perception

The process of organizing and interpreting sensory information, enabling recognition of meaningful objects and events.

Top-Down Processing

Information processing guided by higher-level mental processes, drawing on expectations and experience; it is concept-driven and moves from the whole to parts.

Selective Attention

The focusing of conscious awareness on a particular stimulus among incoming sensory inputs.

Change Blindness

The failure to notice visual changes in the environment due to a lack of attention directed toward those stimuli.

Absolute Threshold

The minimum level of stimulation needed to detect a particular stimulus at least $50\%$ of the time.

Difference Threshold

The minimum difference a person can detect between two stimuli $50\%$ of the time, also termed the "just noticeable difference" (JND).

Weber’s Law

A principle formulated by Ernst Weber stating that the JND is a constant fraction of the original stimulus intensity ($8\%$ for light, $2\%$ for weight, and $0.3\%$ for tone).

Sensory Adaptation

A reduction in sensitivity to a stimulus following constant, prolonged exposure, which frees attention for new environmental stimuli.

Transduction

The biological process of converting physical sensory signals into neural impulses that the brain can interpret.

Amplitude (Sound)

The physical height of a sound wave measured from the centre line, which dictates the loudness and energy carried by the sound.

Wavelength (Sound)

The speed of wave vibration or number of cycles per second, which determines the perceived pitch of a sound.

Place Theory

A theory of hearing proposing that different sound pitches trigger activity at specific locations along the basilar membrane in the cochlea, with higher pitches stimulating the base.

Frequency Theory

A theory stating that the rate of nerve impulses traveling up the auditory nerve matches the frequency of the sound wave, accounting for low-frequency pitch perception.

Volley Principle

The principle that neural cells alternate rapid firing to achieve a combined frequency greater than $1000\text{ Hz}$, enabling higher-pitch hearing.

Sound Localization

The ability to identify the position and movement of sound sources based on differences in sound wave arrival time and intensity between both ears.

Conductive Hearing Loss

Hearing impairment caused by physical problems conducting sound waves through the outer or middle ear to the cochlea, such as a punctured eardrum or wax buildup.

Sensorineural Hearing Loss

Also called nerve deafness, hearing loss caused by damage to the cochlea's hair cell receptors or auditory nerves from aging, genetics, or loud noise.

Accommodation

The process by which the eye's lens changes its curvature and thickness to focus near or far images on the retina.

Blind Spot

The point where the optic nerve leaves the eye, creating an area void of photoreceptor cells.

Rods

Retinal photoreceptors located in the periphery that register black, white, and gray tones, functioning best under low-light conditions.

Cones

Retinal photoreceptors clustered in the fovea/center that detect sharp detail and colors, functioning best in daylight or well-lit settings.

Trichromatic Theory

The theory (Young-Helmholtz) proposing that the retina contains three color receptor types sensitive to red, green, or blue, which combine to produce color vision.

Opponent-Process Theory

The theory that opposing retinal processes (red-green, yellow-blue, black-white) enable color vision, explaining negative afterimages and color blindness.

Gate Control Theory

The theory that the spinal cord contains a neurological gate that opens via small nerve fibers to allow pain signals to the brain and closes via large nerve fibers to block pain.

Phantom Limb Sensations

Sensory experiences and pain perceived as originating from a body part that has been amputated.

Papillae

Structures on the tongue that contain taste buds, hosting receptor cells for sweet, sour, salty, bitter, umami, and oleogustus sensations.

Sensory Interaction

The principle that one sense can influence and interact with another, such as how the smell of food impacts its perceived flavor.

Olfaction

The sense of smell, involving $50\text{ million}$ receptor neurons in the olfactory epithelium that bypass the thalamus when transmitting signals to the brain.

Kinesthesis

The sensory system responsible for detecting the position and movement of individual body parts, essential for muscle memory.

Vestibular Sense

The sensory mechanism for balance, head position, and movement, situated within the semicircular canals and vestibular sacs of the inner ear.

Synesthesia

A neurological condition in which the stimulation of one sensory or cognitive pathway leads to involuntary experiences in a second pathway.

Schemas

Organized frameworks of knowledge that help organize and interpret sensory information, guiding expectations and judgment.

Perceptual Set

A mental predisposition or readiness to perceive one thing and not another based on previous experiences, context, or culture.

Gestalt

An organized whole; a psychological perspective emphasizing the human tendency to integrate pieces of information into meaningful whole objects.

Figure-Ground

The perceptual organization of the visual field into distinct objects (the figures) that stand out from their surroundings (the ground).

Similarity

A Gestalt grouping principle stating that visual elements with similar features (such as color or shape) are perceived as belonging together.

Closure

A Gestalt grouping principle describing the brain's tendency to fill in gaps in visual figures to perceive a single, complete form.

Proximity

A Gestalt grouping principle stating that elements located close to one another are perceived as a unified group.

Visual Cliff

A laboratory apparatus with a drop-off covered by glass used to assess depth perception in human infants and young animals.

Retinal Disparity

A binocular depth cue that uses the difference between the two slightly different images cast on each retina to calculate distance.

Convergence

A binocular depth cue involving the neuromuscular act of rotating the eyes inward to focus on nearby objects.

Interposition

A monocular depth cue in which an object that partially blocks another object is perceived as being closer.

Relative Clarity

A monocular cue for depth where light passing through atmospheric haze makes distant objects appear blurrier than clear foreground objects.

Relative Size

A monocular depth cue where an object casting a smaller retinal image is judged to be farther away than an identical object casting a larger image.

Texture Gradient

A monocular cue for depth where gradual shifts from distinct, coarse texture to fine, indistinguishable texture indicate increasing distance.

Linear Perspective

A monocular depth cue where parallel lines appear to converge toward a single vanishing point as they recede into the distance.

Perceptual Constancy

The tendency to perceive familiar objects as having a constant shape, size, and color despite changes in lighting, perspective, and retinal images.

Apparent Motion

The perceptual illusion of movement produced when two stationary visual stimuli are flashed in rapid, alternating succession.